Electron-discharge device



July 28, 1925.

R. W. KING ELECTRON DISCHARGE DEVICE Filed July 22, 1919 /n ven for; Robe/f W K/ng M A1737.

Patented July 28, 1925.

UNITED STATES PATENT OFFICE.

ROBERT W. KING, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED. OF YORK, N. 1., A CORPORATION OF NEW YORK.

ELECTRON-DISCHARGE DEVICE.

Application filed July 22, 1919. Serial No. 312,597. I

To all whom it may concern:

Be it known that 1, ROBERT W. KING, a citizen of the United States, residing at New York, in the county of New York, State of New York, have invented certain new and useful Improvements in Electron- Discharge Devices, of which the following is a full, clear, concise, and exact description.

The invention relates to electron discharge devices employed for amplifiers, repeaters, rectifiers, detectors, etc. The invention relates particularly to devices of this type which are adapted to be used for high voltages and has for an object (a) to prevent leakage between leadin -in wires at high voltages, and (b) to avoid ionization of the gas in a vacuum tube at high voltages due to the emission of occluded gases from the electrodes, particularly the grid.

The first-mentioned object is accomplished by the substitution for the usual press in which the leading-in wires are sealed, of an inwardly projecting dome from which arises a glass arm or arms which are widely separated and which serve to support the electrodes.

The second-mentioned object is accomplished by using a highly refractory metal, such as molybdenum'or tungsten wire instead of nickel or other metal for the electrodes, and particularly the grid. It is possible to heat molybdenum or tungsten dur-' ing the manufacture of the vacuum tube to a hi her temperature than nickel and it is there y possible to more effectively drive out occluded gases. It is not feasible, however, to seal molybdenum or tungsten into glass becauseof the wide difference in the coefficients of expansion of glass and the metals named. Accordingly, a nickel, copper or iron leading-in wire is employed, the more refractory molybdenum or tungsten being fastened thereto in a suitable manner such as by a soft metal sleeve which clamps the abutting ends 'of the wires. For further details of the invention reference may be made to the drawings, in which the figure shows in perspectiv'ea vacuum tube embodying the above-mentioned features.

In the figure the inwardly projecting neck portion 1 of the vacuum tube 2 is not terminated in the usual so-called press or squash but in a dome, which makes it possible to secure a wide separation for the glass supporting rods 3, 4, 5 and 6 arising from the dome. One of the electrodes to be supported is shown as a'tensioned helical filamentary cathode 7 which may be of tungsten or of the alkaline earth oxide coated type. The grid 8 is shown as in the-form of a helix and is preferably of molybdenum or tungsten. The anode 9 is cylindrical in form and is su ported by a -w1re 10 which may be of mo ybdenum or tungsten and which forms a cradle having the parallel circular portions 11, 12 for supporting the cyl ndrical anode. The anode may be fastened to the circular portions 11 and 12 by means of the wires as shown at 13 which pass through apertures in the anode and embrace the cradle.

In order to avoid sealing the refractory wires 10 and 14 into the glass rods 3 and 5,

both of which are preferably of molybdenum or tungsten, these wires are supported as indicated by the second feature of the invention above-mentioned. To this end there are sealed into the glass rods 3 and 5, the wires 15 and 16 which have a coefficient of expansion about the same as that of glass and may be of nickel, copper or iron. The wire 14 is connected to the wire 16 by a soft metal clamp 17 which embraces the abutting ends of these wires. A similar arrangement is employed at 18 for the Wire 15 and the extension 10 of the cradle. Electrical connection may be made to the electrodes by means of the lead wires 19, 20, 21, 22 which are sealed into the dome and which ma consist of stranded wires as shown, WhlCh may be suitably insulated.

The wires rising from posts 4: and 6, and which lead to the filament, may be of nickel and need not be tungsten due to the comparatlvely low voltage applied to the filament.

What is claimed is:

1. An electron discharge device comprising a tube, a grid and supporting arm of refractory metal, a wire sealed into said tube, and a metallic clamp around e ends of said arm and said wire.

2. An electron discharge device comprising an evacuated vessel, a tubular member projecting inwardly from said vessel, a wire sealed into said tubular member, a substantially cylindrical wire frame supported by said wire, an electrode supported by said frame, and a leading-in wire attached to said frame. v

3. An electron discharge device comprising a continuous wire cradle having a substantially cylindrical supporting portion, a cylindrical electrode supported thereby, and a metallic support for said cradle. I

4. An electron discharge device comprising a continuous wire cradle having parallel circular supporting portions, a cylindrical anode supported thereby, and a metallic support for said cradle.

5. In an electron discharge device, a cradle comprising a wire bent to form two substantially parallel circular portions, a cylindrical electrode and supporting connections between said electrode and said circular portions.

In witness whereof, I hereunto subscribe my name this 18th day of July, A. D. 1919.

ROBERT W. KING. 

